Dynamo-electric-machine control



v B. M. LEECE. DYNAMO ELECTRIC MACHINE CONTROL.

APPLICATION FILED NOY- 23, 1918'.

1,390,452; v Pat'entedSept. 13, 1921.

UNITED STATES PATENT OFFICE.

BENNETT M. LEECE, OF CLEVELAND, OHIO, ASSIGNOR TO THE LEEOE-NEVILLE COM- PANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

I DYNAMO-ELECTRIC-MACHINE CONTROL.

Specification of Letters Patent. vPatented Sept, 13, 1921.

Original application filed December 22, 1913, Serial No. 808,064. Divided and this application filed November 23, 1918.

To all whom it may concern:

Be it known that I, BENNETT M. Lnnon,

a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Im rovement in Dynamo-Electrio- Machine ontrols, of which the following is a full, clear, and exact description.

This invention relates to the control of dynamo electric machines, and has special utility in lighting or starting and lighting systems used in connection with internal combustion engines of vehicles such as automobiles and boats. division of my rior application, Serial No. 808,064, filed ecember 22, 1913, which application resulted in Patent No. 1,286,182, granted November 26, 1918.

The chief object of the invention is to provide improved means for preventing a rise in voltage across the terminals of the main field winding of the machine when the latteris disconnected from the battery. More particularly the invention aims to provide a circuit controlling means which on disconnecting the battery and dynamo electric machine causes a quick collapsing of the field, particularly in a machine whose field is roduced by differentially wound coils inc uding shunt coils and opposing series coils.

The invention may be briefly summarized as consisting in certain novel .combinations and arrangements of parts described in the specification and set forth in the appended claims.

The single figureof the drawing shows diagrammatically a starting and lighting system embodying my invention although t e features of the present invention are not confined to a system having the dual functions of starting and lighting, but have utility in a system employed for lighting or battery charging purposes only.

The. system herein shown includes a storage battery 10, and a dynamo electric machine 11. This machine, which is preferably of the four-pole type includes a field member 12, and an armature 13, the field member having two oppositely disposed wound poles 14 and two oppositely disposed short consequent poles 15 which are unwound.

This application is a.

Serial No. 263,851.

ings are additive or assist each other so as to provide maximum field strength or torque, and when the machine is changed to a generator the current is reversed in the series winding so that the field produced thereby opposes the field produced by the shunt winding with the result that the current passing through the series winding has a regulating action, the opposing and .regu-lating effect varying with the speed.

I utilize two main brushes 18, which are in this case disposed ninety degrees apart, and to which the main conductors extending between the dynamo electric machine and battery are connected. I also utilize an auxiliary brush 19 which is between the main brushes, and I connect one terminal of the shunt field winding to this brush and the other. terminal to one of the main brushes. This brush is located in such a position that the voltage, and consequently the current assing through the shunt winding 17 is a ected by distortion or shifting of the field due to change in speed. The voltage between the terminals of the shunt field winding is considerably less than the voltage between the main brushes, and if the auxiliary brush is just midway between the brushes 18, the voltage impressed on the shunt field winding will be half that of the voltage between the main brushes. I prefer to mount this auxiliary brush 19 so that it may be adjusted within suitable limits relative to the main brushes circumferentially about the commutator so that the effective voltage which'is impressed on the shunt winding and consequently the value of the current passingthrough the shunt winding maybe varied. This admits of variation in current output.

This brush admits of closer regulation than is produced simply by the differential action of the field windings, for when the speed varies there is more or less of a shifting or distortion of the main field flux passing between the armature, and the main field plishing this with an auxiliary brush which affords the regulating action, I am enabled to use in the shunt winding a large conductor and pass through the winding a current which even at low speeds saturates the field.

In consequence, I need not employ a large number of turns in the shunt winding; the size of the machine as a whole can be made quite small, and the machine will begin to generate at a low engine speed.

In the controlof themachine, I utilize a switch which not only serves to connect and disconnect the dynamo electric machine 11 and storage battery 10, but has an additional important function. This switch, as here shown, has four contacts 20, 20", 20 and 20 and is provided with a movable switch member 20, which is pivoted between its ends and is adapted to be moved to a position such as to engage and bridge the contacts 20 and 20, or to engage and bridge the contacts 20 and 20.

It will be observed by tracing the circuits, that connection is made from one of the main brushes 18 to the series winding on one pole, then to the series winding on the opposite pole, and then connection is made by a conductor 21 and suitable branch conductors to contacts 20 and 20, and that connection is made from the other main brush 18 by conductor 22 to one terminal of the battery, the opposite terminal of the battery being connected by conductor 23 to contact 20. Alsothe contact 20 of the switch is connected by conductor 24 to the conductor 22 at a point between the battery and the dynamo electric machine. At 25 are shown in conventional manner, the lamps'of the lighting circuit which are connected or may e connected througha suitable switch 26 to the battery-dynamo-electric machine circuit, so that said lighting circuit may receive current from either the battery or generator.

In consequence, When the switch is in the position shown in the drawing, the battery and dynamo electric machine are connected, and if it is moved to this position, with all parts idle, the machine will serve as a motor to crank the engine, and as soon as the engine is started, it will drive the dynamo electric machine, andwhen the voltage of the machine exceeds that of the battery, the machine will .begin charging the battery.

If now, it is desired to render the current generating apparatus inoperative, while the engine is running, the movable switch member is moved to the position shown by dotted lines so as to engage the contacts 20 and 20.

WVhen the switch is shifted to this position, not only does it disconnect the battery and dynamo electric machine, but it short circuits the machine, and thus eliminates all danger of the voltage in the shunt winding building up and of the winding burning out, as might be the case if the machine were run idle on open circuit.

When this switch short circuits the machine, the field is instantly collapsed or killed for the reason that the voltage between the terminals of the shunt winding is greatly reduced, andwhile the short circuiting of the generator has a tendency to increase the ampere turns of the series winding, this assists in the collapsing of the field due to the fact that the field produced by the series winding opposes that produced by the shunt winding.

Thus the circuit controlling and short circuitin switch has special utility in a differential y wound machine having a series winding which during generation produces a field opposing that produced by the shunt winding, and in practice the invention has proven to be especially efiicacious in a third brush differentially wound machine such as herein illustrated and described wherein the voltage across the terminals of the shunt field winding is a fraction of the main terminal voltage.

The engine may drive the dynamo electric machine or be driven thereby in any suitable manner, but preferably through a single power transmitting agency -consisting of chain and sprocket gearing connecting or extending between the engine crank shaft or a continuation thereof and the shaft of the dynamo electric machine.

Having described my invention, I claim:

1. In a system such as described, a storage battery, a dynamo electric machine for charging the same and provided with differential series and shunt field windings, and switching means for short circuiting the dynamo electric machine and disconnecting the latter .from the battery.

2. In-a system such as described, a storage battery, a dynamo electric machine for charging the same, said dynamo electric machine having main brushes and .an auxiliary brush and having a main shunt field winding connected between the auxiliary brush and one of the main brushes. a series field winding ,which when the machine is generating produces a field opposing the field produced by the shunt winding. and switching means for connecting and disconnecting the battery and dynamo electric machine and for short circuiting the latter when it is disconnected from the battery.

3. In a starting and lighting system adapted to be employed in connection with an internal combustion engine, a battery, 0. dynamo electric machine adapted to serve as i the battery,

a motor to crank the engine and to be driven by the engine as a generator, said dynamo electric machine having diiferentiall wound field coils, and a controlling switc in the battery-dynamo electric machine circuit and having connections for short circuiting the dynamo electric machine when the latter is disconnected from the battery.

4. In a starting and lighting system adapted to be employed in connection with an internal combustion engine, a third brush differentially wound dynamo electric machine adapted to serve as a motor to crank the engine and as a battery charging and lighting generator after the engine is start ed, a storage battery, a switch for connecting the machine to and disconnecting it from and having connections for short circuiting the machine when it is disconnected from the battery.

5. In a starting and lighting system adapted to be employed in connection with an internal combustion engine, a dynamo electri machine adapted to serve as a motor to crank the engine, and then to be driven as a generator, said (1 namo electric machine having main brus es and an auxiliary brush, and a field member having a shunt winding and a series winding, the former being connected between one of the main brushes and the auxiliary brush, the said windings producing fields which assist each other when the machine is serving as a mo tor, and which oppose each other when the machine is serving as a generator, in combination with a storage battery adapted to supply current to the machine when it is serving as a motor, and adapted to be charged by the machine when it is serving as a generator, and means for connecting and disconnecting the battery and dynamo electric machine and for protecting the shunt field winding against abnormal voltage betweenits' terminals.

6. In a startin and lighting system adapted to be emp oyed in connection with an internal combustion engine, a battery, a third brush current output regulated dynamo electric machine driven at variable speed by the engine for charging said battery, a circuit from the dynamo electric machine to the battery, and switch means intercalated in said circuit for disconnecting said dynamo electric machine from said battery and concomitantly" forming a conducting path between the terminals of said dynamo electric machine.

In testimony whereof I hereunto afiix my signature.

BENNETT M. LEECE. 

